Organic light emitting device having surface-treated bottom electrode

Abstract

Disclosed is a method of manufacturing an organic light emitting device, which comprises the steps of successively stacking a bottom electrode, an organic layer including an emission layer, and a top electrode, the method further comprising the step of: surface-treating the bottom electrode with ion beam etching before stacking the organic layer. By effectively removing impurities such as polymer materials or oxidation films, which are formed on the bottom electrode of the organic light emitting device, not only electron injection and hole injection in the organic light emitting device progress smoothly, but also an operation voltage is lowered and performance reliability can ensured because the surface roughness of the bottom electrode is maintained at the same level before and after ion milling.

1. A method of manufacturing an organic light emitting device, which comprises the steps of successively stacking a bottom electrode, an organic layer including an emission layer, and a top electrode, the method further comprising the step of:
 removing impurities by surface-treating the bottom electrode with ion beam etching before stacking the organic layer, wherein the ion beam etching is carried out using ions having no reactivity with a surface of the bottom electrode such that the electrode surface can be maintained as substantially flat surface having the substantially same level of surface roughness before and after the ion beam etching. 
 
     
     
       2. The method according to  claim 1 , wherein a surface of the bottom electrode is etched to a depth of 5 to 200 Å by surface-treating the bottom electrode with the ion beam etching. 
     
     
       3. The method according to  claim 1 , wherein the impurities include oxidation films of metals. 
     
     
       4. The method according to  claim 1 , wherein the bottom electrode is formed as a negative electrode (cathode). 
     
     
       5. The method according to  claim 1 , wherein the bottom electrode is made of any one selected from the group of metal elements including Al, Ca, Mg, Ag, Cr, Ti, Pd, Au, Mo and Ir, or an alloy consisting of at least two kinds of the metal elements. 
     
     
       6. The method according to  claim 1 , wherein the bottom electrode is made of one transparent electrical conductive oxide selected from the group consisting of ITO (Indium-Tin Oxide), IZO (Indium-Zinc Oxide), ZnO and SnO 2 . 
     
     
       7. The method according to  claim 1 , wherein the ion beam etching, carried out using ions having no reactivity with a surface of the bottom electrode, provides only an impact action on the surface of the bottom electrode and impurities existing thereon. 
     
     
       8. The method according to  claim 1 , wherein the ion having no reactivity with the surface of the bottom electrode includes an argon ion (Ar + ), a gallium ion (Ga + ) or an argon/gallium mixture gas ion (Ar + and Ga + ). 
     
     
       9. An organic light emitting device comprising:
 an ion beam etching treated bottom electrode; 
 an organic layer including an emission layer; and 
 a top electrode, 
 wherein the organic light emitting device is manufactured by successively stacking the bottom electrode, the organic layer including the emission layer, and the top electrode, 
 wherein the surface of bottom electrode adjacent to the organic layer is treated with ion beam etching using ions having no reactivity with the surface of the bottom electrode before stacking the organic layer to remove impurities, and 
 wherein the surface of the ion beam etching treated bottom electrode has a substantially flat surface having the substantially same level of surface roughness before and after the ion beam etching. 
 
     
     
       10. The organic light emitting device according to  claim 9 , wherein the bottom electrode is formed by stacking an electrical conductive material on a substrate or may be a substrate itself made of an electrical conductive material. 
     
     
       11. The organic light emitting device according to  claim 9 , wherein the organic light emitting device is used in a display apparatus, and the bottom electrode is patterned in such a manner as to allow the display apparatus to be driven according to an active matrix type or a passive matrix type. 
     
     
       12. An ion beam etching treated bottom electrode for an organic light emitting device, on or above which an organic layer including an emission layer is to be directly or indirectly stacked, and which is surface-treated with ion beam etching using ions having no reactivity with the surface of the bottom electrode, wherein the surface of the ion beam etching treated bottom electrode has a substantially flat surface having the substantially same level of surface roughness before and after the ion beam etching. 
     
     
       13. The organic light emitting device according to  claim 9 , wherein a surface of the bottom electrode is etched to a depth of 5 to 200 Å by surface-treating the bottom electrode with the ion beam etching. 
     
     
       14. The organic light emitting device according to  claim 9 , wherein the impurities include oxidation films of metals. 
     
     
       15. The method according to  claim 1 , wherein the bottom electrode is wholly or partially patterned by a photolithography process when the bottom electrode is formed, and impurities coming from the photolithography process are removed by surface-treating the bottom electrode with the ion beam etching. 
     
     
       16. The organic light emitting device according to  claim 9 , wherein the bottom electrode is wholly or partially patterned by a photolithography process when the bottom electrode is formed, and impurities coming from the photolithography process are removed by surface-treating the bottom electrode with the ion beam etching.